<template>
  <div>
    <router-link class="header-abs" tag="div" to="/"
    v-show="showAbs"
    >
      <div class="iconfont back-icon">&#xe656;</div>
    </router-link>
    <div class="header-fixed"
    v-show="!showAbs"
    :style = "opcityStyle"
    >
      <router-link to="/">
        <div class="iconfont header-fixed-back">&#xe656;</div>
      </router-link>
      景点详情
    </div>
  </div>
</template>

<script>
export default {
  name: '',
  data () {
    return {
      showAbs: true,
      opcityStyle: {
        opcity: 0
      }
    }
  },
  methods: {
    handleScroll () {
      const top = document.documentElement.scrollTop
      // console.log(document.documentElement.scrollTop)
      if (top > 60) {
        let opcity = top / 140
        opcity = opcity > 1 ? 1 : opcity
        this.opcityStyle = {
          opcity
        }
        this.showAbs = false
      } else {
        this.showAbs = true
      }
    }
  },
  activated () {
    window.addEventListener('scroll', this.handleScroll)
  },
  deactivated () {
    window.removeEventListener('scroll', this.handleScroll)
  }
}
</script>

<style lang="stylus" scoped>
@import "~styles/varibles.styl";
.header-abs
  position absolute
  left: .2rem
  top:  .2rem
  width: .8rem
  height .8rem
  line-height .8rem
  border-radius: .4rem
  background rgba(0,0,0,.8)
  text-align: center
  .back-icon
    color:#fff
    font-size: .4rem
.header-fixed
  z-index: 2
  position fixed
  top: 0
  right: 0
  left: 0
  overflow: hidden
  height  $headerHeigth
  line-height $headerHeigth
  text-align center
  color: #fff
  background $bgColor
  font-size: .32rem
  .header-fixed-back
    position absolute
    top: 0
    left: 0
    width: .64rem
    text-align: center
    font-size: .4rem
    color: #fff
</style>
